Perforated, flow-through rubber or plastic floor mats are useful for providing a safe, non-slip surface for people and other traffic moving in damp locations. This is accomplished by keeping the feet of the pedestrians above damp or particulate-rich, encumbered, or otherwise slippery floors. Liquid or particulate matter flows through perforations, formed by space between both upper and lower ribs, as depicted in the appended drawings. As a result the upper surface of the mat is kept relatively clear of liquid or particles.
Conventionally, the upper surface of the floor mat is constituted by a number of narrow, parallel, plastic or rubber strips, or ribs. Usually these are separated by a distance of approximately the width of an individual rubber strip, as depicted by the appended drawings. Often, such strips have anti-skid corrugations on their top surfaces to provide a high-friction walking surface, since smooth vinyl can become slippery under some conditions.
However, in many cases, the anti-skid structures on the top surfaces of the upper portion of the floor mat can create additional hazards. For example, the structures such as corrugations may hold loose particulate matter, rendering that mat's surface more slippery than that possible with a smooth upper surface. Also, it has been discovered through use that sometimes corrugated surfaces do not exhibit as much friction as that provided by smooth flat mats.
It is well known that some fluids can form a film on smooth, plastic mat surfaces, rendering them unacceptably dangerous. Consequently, some floor mat systems are designed so that upper surfaces are coated with an abrasive grit material that will not allow formation of a liquid slick on the mat's surface, and will provide additional traction because of the abrasive nature of the grit.
It is well known to apply a binder such as urethane and abrasive grains to an upper surface of the mat. Then the binder is cured to produce a coated, abrasive, non-slip product. Eventually, one or more coats are applied over the abrasive grains, and then cured, to help hold the abrasive grains, or grit to the mat surface.
A number of curing techniques are well known, and include heat or radiation curing. This is very common in the application of abrasive mineral particles, also known as grit, to polyvinyl chloride mating. As disclosed in U.S. Pat. No. 4,336,293, incorporated herein by reference, the process for making the mat includes placing the mat in an oven for 30 minutes at 120° C. to partially cure the mat. Then the grit particles are applied covered with an overcoat, known as a sizing coating. The mat is then cured in an oven at 130° C. for four hours.
The various forms of heat and radiation curing are well known. A number of examples are found in the following patents: U.S. Pat. Nos. 5,033,979; 4,345,545; 4,385,239; 4,457,766; 4,547,204; 4,588,419; 4,336,293; 4,196,243; and, U.S. Pat. No. 4,608,287. All of the aforementioned patents are incorporated herein by reference as constituting background material depicting conventional techniques for adhering grit to plastic surfaces.
Normally the industrial processes for producing such mats are long and complex, dealing with a number of intermediate steps, and the use of such additional elements as craft release paper, photosensitizer, or other complicating elements. All of this contributes added cost to the overall industrial process.
A major problem with all of the aforementioned techniques resides in the substantial processing times needed to attach the grit to the plastic surfaces. Most of the processes include heat treatment or radiation treatment, further adding time and expense to the manufacturing process on a final product that is meant to be inexpensive. To save time and expense in the processing, a number of alternatives have been proposed. Of particular interest is the use of urethane adhesive to hold the abrasive grit to a plastic mat surface.
Urethane adhesives work very well with plastic material, and are very easy to apply for purposes of adhering grit to the surface of a plastic structure. Because of the fast acting characteristics of urethane, multiple processes can be rapidly carried out as multiple coats of urethane and grit are added to the plastic surface. The result is excellent non-skid surface suitable for safety floor mating, or other related uses.
Unfortunately, there are limitations to the final product. The mats that are treated with urethane to hold this abrasive grit are vulnerable to loosening and loosing the grit under certain conditions. If the plastic mats are bent, rolled, otherwise distorted, the grit will be loosened and come away from the mat, creating a hazard in itself, and eventually leaving a bare plastic surface on the mat. The same problems are found with epoxy adhesives.
In order to prevent this from happening, it is accepted manufacturing technique to apply the grit held by epoxy or urethane adhesive to only relatively thick, inflexible mat sections. Normally, such mats are not meant to be moved, and are usually held in raised frameworks on a floor or other substrate. Examples of such holding arrangements and relatively thick mats are found in the following U.S. patents: U.S. Pat. Nos. 6,740,380; 6,635,331; 6,531,203; 6,444,284; 6,440,525; 6,352,757; 6,319,584; 6,127,015; 6,068,908; 6,042,915; 5,882,764; and, U.S. Pat. No.5,985,538. All of the aforementioned patents are incorporated with herein by reference as depicting the conventional state of the floor mat art.
All of the aforementioned arrangements are meant to hold floor mat sections in a fixed, unmoving arrangement. These are generally very effective arrangements, but have certain drawbacks. For example, frameworks must be erected to hold the mat sections. This is often time consuming and awkward. It is also very difficult to remove the frames for cleaning or redistribution of the mat sections. In many cases, indentations or recesses are made in the floor or substrate in order to accommodate a relatively thick mat section. Mat sections must remain relatively rigid in order to avoid deformation and loss of the grit material. This means that the mat section must be relatively thick, and thus heavy. As a result, they are often difficult to remove for cleaning underneath them.
In many situations requiring floor mats, light, rollable floor mats are used because they can be easily adjusted, and easily removed for cleaning. Examples of light gage (approximately ¼ inch to ½ inch thick) mat systems are depicted in the following U.S. patents: U.S. Pat. Nos. 6,578,324; 6,405,495; and, U.S. Pat. No.5,992,105. All of these are incorporated by reference as depicting the state of light gage plastic floor mats. These mats are light, easy to use and deploy, and can be rolled so that the floor underneath can be easily cleaned. Unfortunately, they also have a bit of limitation.
The plastic upper surfaces of these mats are constituted by a series of ribs or strips that have smooth upper surfaces. When grease or oil are allowed to collect, these surfaces can become slick and the mats may become somewhat slippery. Accordingly, such mats would benefit from the application of permanent grit upper surfaces. Unfortunately, rolling of the mats or other substantial deformation may cause conventional grit arrangements to come loose. Even heat-treated, polyvinyl chloride surfaces may not be capable of holding grit when rolled or otherwise substantially deformed.
Accordingly, there is a need for an arrangement to hold abrasive grit to the upper surface of a light, rollable floor mat without loosening or degrading the grit on the plastic matting material. Consequently, an improved floor mat would be produced by a process that is both simple, and time-efficient. Further, the process would not require substantial additional equipment or expertise.